When I rebuilt my differential and installed the Wavetrac. I stuck a 1/2 x 1/2" cylindrical neodymium magnet on the end of the fill plug. When I checked the fluid after a couple thousand miles I did notice some metal accumulated on the magnet. I also noticed the fluid was still very clean looking. The magnetic had not moved.

My point is you could just buy a magnet and stick it to the end of your current plug. You would probably end up with a more powerful magnet for the same price. McMaster has a nice selection of high pull rare earth magnets. This is the one I bought. It was for another project, but I used it on the differential fill plug to catch bits of bearing and gear. It works great.

When I rebuilt my differential and installed the Wavetrac. I stuck a 1/2 x 1/2" cylindrical neodymium magnet on the end of the fill plug. When I checked the fluid after a couple thousand miles I did notice some metal accumulated on the magnet. I also noticed the fluid was still very clean looking. The magnetic had not moved.

My point is you could just buy a magnet and stick it to the end of your current plug. You would probably end up with a more powerful magnet for the same price. McMaster has a nice selection of high pull rare earth magnets. This is the one I bought. It was for another project, but I used it on the differential fill plug to catch bits of bearing and gear. It works great.

You're pretty positive that it won't come off the drain plug right? Last thing I need is the magnet travel to the piston & rod....

I wouldn't bet my life on it, but maybe my motor. Once those rare earth magnets are stuck, they take considerable force to remove.

Now consider the forces present on the magnet inside the oil pan. Maybe you have some oil rushing by and some force transferred from bumps in the road, but I would think unless you take the car off a jump, it should stay put.

Like I said the one I put on my differential fill plug didn't move at all.